Transformer with regulating choke coils



Jan. 3, 195() A. MEYERHANS TRANSFORMER WITH REGULATING CHOKE COILS Filed Sept. 20, 1946 2 Sheets-Sheet 1 Jan. 3, 1950 A. MEYERHANS 2,493,683

TRANSFORMER WITH REGULATING cHoxE coILs Filed Sept. 20,. 1946 2 Sheets-Sheet 2 Patented Jan. 3, 1950 TRANSFORMER WITH REGULATING CHOKE COILS August Meyerhans, Rieden, near Baden, Switzer- Y land, assignor to Aktiengesellschaft Brown, Boveri & Cie., Baden, Switzerland Application September 20, 1946, Serial No. 698,3.66

In Switzerland September 21, 1945 7 Claims. (Cl. 171-119) Transformers with regulating choke coils particularly for electric Welding purposes, are known, where an enclosed main core for the windings of the transformer and an adjoining auxiliary core for the regulating choke coil is provided, the lines of force of the latter passing partly through the yoke of the main core. Transformers of this kind possess the disadvantage that due to the unfavourable arrangement of the air gaps in the choke coil vibrations and humming occur, and the construction of the transformer is complicated and expensive.

The present invention concerns a transformer with regulating choke coil, particularly for Welding, with an enclosed main core for the Windings of the transformer and an adjoining auxiliary core for the regulating reactor, the lines of force of the latter passing partly through the yoke of the main core, the aforementioned disadvantages of this kind of transformer being avoided according to the invention by the transformer and the choke coil possessing a common core column which penetrates the transverse yokes.

Constructional examples of the invention are illustrated diagrammatically in the accompanying drawings where Figs. 1 and 3 show a transformer and choke coil in longitudinal section, Whilst Fig. 2 is cross-section of Fig. 1.

In Fig. 1 a is the common core column with transverse yokes b1, bz, b3 for both the transformer windings and choke coil, whilst cl-ca are slide or longitudinal yokes forming magnetic return flow paths. The core a as illustrated in Fig. 2 is seen to be a laminated cylinder, the laminations of which are arranged radially. The primary winding d and the secondary Winding e of the transformer are located on the part of core column a bounded by the yokes b2, b3. The regulating choke coil winding f is located on the part of the core column bounded by the yokes b1, b2 and forms the auxiliary core. The longitudinal yokes are disposed in a cage-like form around the core.

With the constructional form shown in Figs. 1 and 2, the transverse yokes consist of laminations arranged perpendicular to the core axis, whilst the longitudinal yokes are formed by laminations arranged parallel to planes passing through the core axis. ported by the transverse yokes b2, b3; they possess extensions which project freely along the length of core column of the choke coil. To facilitate the assembly of the core elements, the transverse yokes b2, ba are provided with flat supporting The longitudinal yoke parts are supsurfaces for the longitudinal yokes. Assembly is achievedwith the aid of press rings g1, g2 ,which are pushed over the longitudinal yokes from outside; the necessary pressure is obtained for instance by means of press bolts. The transverse yoke b1 which closes the magnetic circuit of the auxiliary core carries the choke coil winding f; both have a certain amount of radial clearance betweenl the core column and the vlongitudinal yokes. The supporting element 7L for the yoke and winding can be provided with an extension z' which slides in the central bore of the core column and*V acts as a guide. Transverse yoke b2 common to both transformer and choke coil is preferably provided with an air gap relative to the longitudinal yokes,'this gap being achieved by the insertion of Apieces of insulating material, whereby as the depth of penetration of the movable transverse yoke carrying the choke coil is increased an increasing and adequate part of the main transformer flux is forced to ow round the choke coil windingto enable the ignition voltage to be sufciently increased for small welding currents.

With the constructional example shown in Fig. 3 the core columnwhich penetrates the yokes is divided into' two coaxial parts inside the winding of the choke coil f. The part of the core column further removed from the transformer is movable with regard to the'stationary winding of the choke coil. The longitudinal and transverse yokes are in this case composed of E-shaped ,stacks of 'laminations which are pressed against the core columns byimeans of bands.

The arrangement according to the invention results in a very compact and light construction for a transformer with choke coil, the production costs being also reduced. A considerable advantage is the automatic increase in ignition voltage when the welding current is reduced, and furthermore the large current range.

The transformer together with the choke coil are expediently located in a circular oil-filled tank which closely surrounds the active part.

The longitudinal yokes can also be pressed on to the transverse yokes by other means than those described. Instead of a magnetic circuit with radial laminated core column, it is also possible to employ a core with two return flow yokes.

I claim:

l. In a combined transformer and regulating choke coil structure, the combination comprising a central radially laminated core; top and bottom laminated yokes positioned transversely of said core; a third laminated yoke positioned.

transversely of said core intermediate said top and bottom yokes and through which said core passes, said intermediate transverse yoke being common to the magnetic circuits of said transformer and choke coil, a plurality of laminated side yokes positioned longitudinally of said core and adjoining said transverse yokes, said side yokes being arranged concentrically about said core with the laminations thereof lying in planes parallel to the core axis; primary and secondary transformer windings surrounding said core between said intermediate bottom transverse yokes, and a choke coil surrounding said core between said intermedi-ate and top transverse yokes, and means for varying the reluctance of that portion of the magnetic circuit associated with said choke coil.

2. A combined transformer and choke coil structure as dened in claim 1 wherein the laminations of said transverse yokes lie perpendicular to the core axis.

3. A combined transformer and choke coil structure as defined in claim 1 wherein an air gap exists between said intermediate transverse yoke and said side yokes.

4. In a combined transformer and regulating choke coil structure, the combination comprising a central radially laminated core; top and bottom laminated yokes positioned transversely of said core; a third laminated yoke positioned transversely of said core intermediate said top and bottom yokes and through which said core passes, said intermediate transverse yoke being common to the magnetic circuits of said transformer and choke coil, a plurality of laminated side yokes positioned longitudinally of said core and adjoining said transverse yokes, said side yokes being arranged concentrically about said core with the laminations thereof lying in planes parallel to the core axis; primary and secondary transformer windings surrounding said core between said intermediate and bottom transverse yokes, and a choke coil surrounding said core between said intermediate and top transverse yokes, said choke coil and top transverse yoke being adjustable longitudinally along said core and side yokes.

5. In a combined transformer and regulating choke coil structure, the combination comprising a central radially laminated core; top and bottom laminated yQkes positioned transversely of said core; a third laminated yoke positioned transversely of said core intermediate said top and bottom yokes and through which said core passes, said intermediate transverse yoke being common to the magnetic circuits of said transformer and choke coil, a plurality of laminated side yokes positioned longitudinally of said core and adjoining said transverse yokes, said side yokes being arranged concentrically about said core with the laminations thereof lying in planes parallel to the core axis; primary and secondary transformer windings surrounding said core between said intermediate and bottom transverse yokes, and a choke coil surrounding said core between said intermediate and top transverse yokes, said choke coil being carried by said top transverse yoke and the latter being adjustable longitudinally along said core and side yokes.

6. In a combined transformer and regulating choke coil structure, the combination comprising a central radially laminated core; top and bottom laminated yokes positioned transversely of said core; a third laminated yoke positioned transversely of said core intermediate said top and bottom yokes and through which said core passes, said intermediate transverse yoke being common to the magnetic circuits of said transformer and choke coil, a plurality of laminated side yokes positioned longitudinally of said core and Iadjoining said transverse yokes, said side yokes being arranged concentrically about said core with the laminations thereof lying in planes parallel to the core axis; primary and secondary transformer windings surrounding said core between said intermediate and bottom transverse yokes, and a choke coil surrounding said core between said intermediate and top transverse yokes, said core being divided into upper and lower c0- axial sections at a point inside of said choke coil, and means for adjusting the upper core section longitudinally of the core axis.

7,A combined transformer and choke coil structure as defined in claim 6 wherein said trans-- verse and side yokes are constituted by E-shaped stacks of laminations.

AUGUST MEYERHANS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name- Date 1,727,224 Waters Sept. 3, 1929 2,089,926 Norris Aug. 10, 1,937 2,133,919 Fries A Oct. 18, 1938 2,415,310 Summerville Feb. 4, 1947 

